Cleaning agent for alloy material, and method for producing alloy material

ABSTRACT

A cleaning agent for an alloy material is provided. The cleaning agent has a pH in a range between 1.5 and 4, inclusive, and contains an anionic surfactant having an SO 3 M group (where M represents a counter ion). It is preferable that the cleaning agent for an alloy material further contains an organic acid. A method for producing an alloy material is also provided. The method includes a step for cleaning the alloy material using the cleaning agent for an alloy material.

TECHNICAL FIELD

The present invention relates to a cleaning agent for alloy material anda method for producing an alloy material.

BACKGROUND ART

Alloy materials are used in various applications because of theiradvantage of having better properties such as mechanical strength,chemical resistance, corrosion resistance, or heat resistance than thoseof pure metal materials. Alloy materials are subjected to processingsuch as polishing (see Patent Documents 1 and 2). The alloy materialsapplied to applications requiring cleanliness are cleaned using acleaning liquid.

PRIOR ART DOCUMENTS Patent Documents Patent Document 1: JapaneseLaid-Open Patent Publication No. 01-246068 Patent Document 2: JapaneseLaid-Open Patent Publication No. 11-010492 SUMMARY OF THE INVENTIONProblems that the Invention is to Solve

Cleaning agents for alloy material applied to alloy materials still haveroom for improvement in view of removal of foreign matters attached tothe alloy material surface and suppression of corrosion of the alloymaterial surface. For instance, if the cleaning agent for alloy materialis improved in the performance of removal of foreign matters attached toan alloy material surface, the alloy material surface may be more easilycorroded.

An objective of the present invention is to provide a cleaning agent foralloy material and a method for producing an alloy material capable ofattaining high cleanliness of an alloy material surface and suppressingdeterioration in quality due to corrosion of the alloy material surface.

Means for Solving the Problems

To achieve the foregoing objective and in accordance with one aspect ofthe present invention, a cleaning agent for alloy material is providedthat includes an anionic surfactant having an SO₃M group (where Mrepresents a counter ion) and has a pH in a range between 1.5 and 4,inclusive.

The cleaning agent for alloy material preferably further includes anorganic acid.

In accordance with another aspect of the present invention, a method forproducing an alloy material is provided that includes a cleaning stepfor cleaning an alloy material using the above described cleaning agentfor alloy material.

The cleaning agent for alloy material preferably has a temperature of60° C. or below in the cleaning step.

The method for producing an alloy material preferably further includes apolishing step performed prior to the cleaning step, and the alloymaterial is preferably polished using a polishing composition in thepolishing step.

In the cleaning step, the alloy material and the cleaning agent foralloy material are preferably brought into contact with each otherbefore the polishing composition attached to the alloy material in thepolishing step is dried.

Effects of the Invention

According to the present invention, high cleanliness of an alloymaterial surface is obtained and deterioration in quality due tocorrosion of the alloy material surface is suppressed.

MODES FOR CARRYING OUT THE INVENTION

Hereinafter, one embodiment according to the present invention will bedescribed.

A cleaning agent for alloy material contains an anionic surfactant andhas a pH in a range between 1.5 and 4, inclusive. At least a part of asurface of an alloy material to which the cleaning agent for alloymaterial according to the present embodiment is applied is composed of amirror surface having been polished using a polishing composition.

The anionic surfactant used in the cleaning agent for alloy material hasan SO₃M group (where M represents a counter ion). Hereinafter, the term“anionic surfactant” refers to an anionic surfactant having the SO₃Mgroup unless otherwise specified.

Specific examples of the anionic surfactant include, for example, alkylsulfonic acid compounds, alkyl benzene sulfonic acid compounds, alkylnaphthalene sulfonic acid compounds, methyltaurine compounds, alkyldiphenyl ether disulfonic acid compounds, α-olefin sulfonic acidcompounds, naphthalene sulfonic acid condensates and sulfosuccinic aciddiester compounds. A polymer or a copolymer having an SO₃M group as aside chain or the like may be also used as the anionic surfactant.Specific examples of the counter ion represented by “M” in the SO₃Mgroup include a hydrogen ion, an alkali metal ion, an ammonium ion, andan alkanolamine ion. Specific examples of the alkali metal ion include,for example, a lithium ion, a sodium ion and a potassium ion.

Among the anionic surfactants, alkyl benzene sulfonic acids or saltsthereof are preferred in view of high cleaning performance and lowcorrosiveness to the alloy material. The carbon number of the alkylgroup in the alkyl benzene sulfonic acids is preferably from 8 to 20,and more preferably from 10 to 15. Dodecyl benzene sulfonic acid or asalt thereof, for example, is suitably used as the alkyl benzenesulfonic acid or salt thereof, respectively.

When the anionic surfactant of sulfonic acid type in which the counterion represented by “M” in the SO₃M group is a hydrogen ion is used amongthe anionic surfactants, the pH of the cleaning agent for alloy materialcan be lowered. Therefore, the pH of the cleaning agent for alloymaterial can be easily adjusted to 4 or less.

The anionic surfactant content in the cleaning agent for alloy materialis preferably 170 ppm by mass (170 mg/kg) or more, and more preferably300 ppm by mass (300 mg/kg) or more. The more the anionic surfactantcontent in the cleaning agent for alloy material, the higher thecleaning performance becomes. The anionic surfactant content in thecleaning agent for alloy material is preferably 15000 ppm by mass (15000mg/kg) or less, more preferably 5000 ppm by mass (5000 mg/kg) or less,and further preferably 2000 ppm by mass (2000 mg/kg) or less. The lessthe anionic surfactant content in the cleaning agent for alloy material,the cleaning agent becomes less corrosive to the alloy material.

The cleaning agent for alloy material may also contain an anionicsurfactant other than the above-described anionic surfactants, anonionic surfactant, a water-soluble polymer, a chelating agent and thelike for the purpose of, for example, improving the cleaning performanceor controlling foaming. Specific examples of the anionic surfactantother than the above-described anionic surfactants include, for example,polycarboxylic acid surfactants and alkyl benzene sulfate estersurfactants. Specific examples of the nonionic surfactant include, forexample, polyoxyethylene alkyl ethers, sorbitan monooleate andoxyalkylene-based polymers having one or more types of oxyalkyleneunits. Specific examples of the water-soluble polymer include, forexample, polyethylene glycol, polyvinyl alcohol, polyvinyl pyrrolidone,and hydroxyethyl cellulose. Specific examples of the chelating agentinclude, for example, amines, amino acids, organic phosphonic acids,phenol derivatives, polyamino phosphonic acids, and 1,3-diketones.

The cleaning agent for alloy material may also contain an anticorrosivein view of suppressing alloy material corrosion. The anticorrosive isnot particularly limited, but is preferably a heterocyclic compound. Inthe heterocyclic compound, the number of ring members of theheterocyclic ring is not particularly limited. The heterocyclic compoundmay be a monocyclic compound or a polycyclic compound having a condensedring.

The cleaning agent for alloy material may also contain an antifoamingagent in view of suppressing foaming caused by, for example, the anionicsurfactant. Specific examples of the antifoaming agent include, forexample, silicone oil-based antifoaming agents and mineral oil-basedantifoaming agents.

When the cleaning agent for alloy material is applied to an alloymaterial that has been polished using a polishing composition containingcolloidal silica as abrasive grains, the pH of the cleaning agent foralloy material is preferably between 1.6 and 3.5, inclusive.

The cleaning agent for alloy material may contain a known acid, base, orsalt as a pH adjuster. Specific examples of the acid include inorganicacids and organic acids. Specific examples of the inorganic acidsinclude, for example, hydrochloric acid, sulfuric acid, nitric acid,hydrofluoric acid, boric acid, carbonic acid, hypophosphorous acid,phosphorous acid, and phosphoric acid. Specific examples of the organicacids include, for example, formic acid, acetic acid, propionic acid,butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid,3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid,n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid,2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid,glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid,adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid,tartaric acid, citric acid, lactic acid, diglycolic acid,2-furancarboxylic acid, 2,5-furandicarboxylic acid, 3-furancarboxylicacid, 2-tetrahydrofurancarboxylic acid, methoxyacetic acid,methoxyphenylacetic acid, phenoxyacetic acid,hydroxyethylidenediphosphonic acid, nitrilotris (methylenephosphonicacid), phosphonobutanetricarboxylic acid, andethylenediaminetetra(methylenephosphonic acid). The pH adjuster ispreferably an organic acid, more preferably at least one selected fromglycolic acid, succinic acid, maleic acid, citric acid, tartaric acid,malic acid, gluconic acid, and itaconic acid, and most preferably citricacid.

Specific examples of the base include, for example, organic bases suchas amines and quaternary ammonium hydroxides, hydroxides of alkalimetals, hydroxides of alkaline earth metals, and ammonia. Specificexamples of the salt include, for example, ammonium salts of acids andalkali metal salts of acids. The pH adjusters may be used singly or incombination of two or more. For example, combination of a weak acid anda strong base, a strong acid and a weak base, or a weak acid and a weakbase exerts a buffering effect on pH.

Specific examples of the alloy material to which the cleaning agent foralloy material is applied include, for example, aluminum alloys,titanium alloys, magnesium alloys, stainless steels, nickel alloys, andcopper alloys. As the aluminum alloys, those containing from 0.1 to 10%by mass of one or more of silicon, iron, copper, manganese, magnesium,zinc, chromium and the like in aluminum as specified in, for example,Japanese Industrial Standard (JIS) H4000:2006 or ISO 209:1989, arepreferred. As the titanium alloys, those containing from 3.5 to 30% bymass of one or more of aluminum, iron, vanadium and the like in titaniumas specified in, for example, JIS H4600:2007, are preferred. As thestainless steels, those containing from 10 to 50% by mass of one or moreof chromium, nickel, molybdenum, manganese and the like in iron asspecified in, for example, JIS G4303:2005, are preferred. As the nickelalloys, those containing from 20 to 75% by mass of one or more of iron,chromium, molybdenum, cobalt and the like in nickel as specified in, forexample, JIS H4551:2000, are preferred. As the copper alloys, thosecontaining from 3 to 50% by mass of one or more of iron, lead, zinc, tinand the like in copper as specified in, for example, JIS H3100:2006, arepreferred. Preferably, the cleaning agent for alloy material accordingto the present invention is mainly applied to alloy materials, but canbe also applied to pure metal materials such as aluminum, titanium,iron, nickel, or copper.

The cleaning agent for alloy material contains water as a solvent or adispersion medium. It is preferable to use water having a low impuritycontent, e.g., deionized water, pure water, super-pure water, ordistilled water.

The cleaning agent for alloy material may also contain a rust inhibitor,an alcohol compatible with water or the like in addition to the aboveingredients as necessary.

A method for producing an alloy material will now be described alongwith operation of the cleaning agent for alloy material.

The method for producing an alloy material includes a polishing step forpolishing an alloy material and a cleaning step for cleaning the alloymaterial.

In the polishing step, at least a part of the alloy material surface ispolished using a polishing composition. Through the polishing step, atleast a part of the alloy material surface is mirror finished. Thepolishing composition contains abrasive grains, which physically polishthe alloy material surface. The kind of the abrasive grains can besuitably changed according to the kind of the alloy material. Examplesof the material of the abrasive grains include silicon oxide, aluminumoxide, cerium oxide, zirconium oxide, titanium oxide, manganese oxide,silicon carbide, and silicon nitride. A single type of abrasive grainsmay be used. Alternatively, two or more types of abrasive grains may beused in combination.

The average particle size of the abrasive grains is, for example, in arange between 5 nm and 400 nm. The average particle size of the abrasivegrains is calculated from the measured value of the specific surfacearea by the nitrogen adsorption method (BET method).

Among materials for abrasive grains, silicon oxide or aluminum oxide ispreferred, and silicon oxide is particularly preferred in view ofincreasing the polishing rate. Specific examples of the abrasive grains(particles) formed of silicon oxide include, for example, colloidalsilica, fumed silica, and sol-gel silica. Among the abrasive grainsformed of silicon oxide, colloidal silica is preferred.

The pH of the polishing composition is adjusted, for example, in a rangebetween 1 and 12, inclusive. The pH of the polishing composition can beadjusted using any of the pH adjusters as described above for thecleaning agent for alloy material. When colloidal silica is employed asthe abrasive grains, the pH of the polishing composition is preferablyadjusted in a range between 8 and 12, inclusive, in view of maintainingthe dispersibility of the colloidal silica. When surface-modifiedcolloidal silica is employed, the pH of the polishing composition canalso be adjusted within the acidic region (e.g., pH in a range between0.5 or and 4.5, inclusive).

The polishing composition may contain an oxidizing agent that chemicallypolishes the alloy material surface. Specific examples of the oxidizingagent include, for example, hydrogen peroxide, peracetic acid,percarbonates, urea peroxide, perchloric acid, perchlorates,persulfates, periodates, and permanganates. Among the oxidizing agents,at least one of hydrogen peroxide and persulfates is preferred in viewof the polishing rate. Specific examples of the persulfates include, forexample, sodium persulfate, potassium persulfate, and ammoniumpersulfate. Among the oxidizing agents, hydrogen peroxide is mostpreferred because of high stability in water and a low environmentalload.

The polishing composition contains water as a solvent or a dispersionmedium. It is preferable to use water having a low impurity content,e.g., deionized water, pure water, super-pure water, or distilled water.The polishing composition may also contain an anionic surfactant, anonionic surfactant, a chelating agent, a rust inhibitor, apreservative, an antifungal agent or the like as necessary.

In the polishing step, a polishing apparatus for polishing metal can beused. Specific examples of the polishing apparatus include a single-sidepolishing apparatus and a double-side polishing apparatus. In thepolishing step, a polishing pad is pressed against the alloy materialsurface and the alloy material or the polishing pad is rotated, whilesupplying a polishing composition to the alloy material surface. Then,the alloy material is physically polished by the friction between thepolishing pad and the alloy material and between the polishingcomposition and the alloy material. When the polishing compositioncontaining an oxidizing agent or the polishing composition having a pHmodifying the alloy material surface is used, the alloy material is alsochemically polished.

Specific examples of the polishing pad include those of polyurethanetype, nonwoven fabric type, and suede type. The polishing pad maycontain abrasive grains. Alternatively, the polishing pad may contain noabrasive grains. Among the polishing pads, that of the suede type notcontaining abrasive grains is suitably used.

In the cleaning step, the alloy material, which has been polished, iscleaned using the cleaning agent for alloy material. The cleaning stepincludes a first cleaning stage, where the alloy material and thecleaning agent for alloy material are brought into contact with eachother, and a second cleaning stage, where the cleaning agent for alloymaterial is removed from the alloy material surface. In the firstcleaning stage, the alloy material is first immersed in the cleaningagent for alloy material before the polishing composition havingattached to the alloy material in the polishing step is dried. Thus, thealloy material surface is prevented from being dried, thereby stickingof foreign matters such as the abrasive grains to the alloy materialsurface is suppressed. Since the surface of the alloy material immersedin the cleaning agent for alloy material is protected by the cleaningagent for alloy material, contact of the alloy material surface with,for example, an oxidative gas is suppressed.

In the first cleaning stage, the cleaning agent for alloy material, inwhich the alloy material is immersed, is then exposed to an ultrasonicwave. Foreign matters attached to the alloy material are effectivelyremoved with the energy caused by generation of bubbles by theultrasonic wave and rupture thereof. When the force, the frequency andthe exposure time of the ultrasonic wave are adjusted according to thealloy material, cleaning efficiency can be improved without damaging thealloy material. The exposure is typically performed with the ultrasonicwave having a frequency of from 20 kHz to 2000 kHz. The frequency ispreferably from 200 kHz to 1000 kHz. The higher the frequency, thebetter the alloy material is prevented from being damaged. The lower thefrequency, generally, the higher the cleaning efficiency becomes.

Since the cleaning agent for alloy material used in the first cleaningstage contains anionic surfactant and has a pH of 4 or less, foreignmatters such as abrasive grains are easily removed from the alloymaterial surface. In addition, since the cleaning agent for alloymaterial has a pH of 1.5 or more, corrosion of the alloy materialsurface is easily suppressed.

The first cleaning stage may be performed in the state where the alloymaterial is either placed at a predetermined position in a stationarystate or being moved. The temperature of the cleaning agent for alloymaterial in the first cleaning stage is preferably 60° C. or below, andmore preferably 55° C. or below in view of suppressing corrosion of thealloy material. The temperature of the cleaning agent for alloy materialin the first cleaning stage is, for example, preferably 1° C. or above,more preferably 10° C. or above, and still more preferably 20° C. orabove. The higher the temperature of the cleaning agent for alloymaterial in the first cleaning stage, the higher the cleaning effectbecomes.

In the second cleaning stage, the alloy material taken out of thecleaning agent for alloy material is immersed in water, and then thewater in which the alloy material is immersed is exposed to theultrasonic wave described above to diffuse the cleaning agent for alloymaterial attached to the alloy material into the water. Thus, thecleaning agent for alloy material is removed from the alloy materialsurface. In the second cleaning stage, when foreign matters that havenot been removed in the first cleaning stage remain on the alloymaterial surface, the foreign matters are diffused into the watertogether with the cleaning agent for alloy material.

The water used in the second cleaning stage is preferably water having alow impurity content, e.g., deionized water, pure water, super-purewater, or distilled water.

The alloy material, which has been cleaned in the cleaning stop isnaturally dried or forcibly dried by, for example, blowing dry air. Thealloy material is machined as necessary to be used in variousapplications, for example, construction materials such as containers andbuilding materials, and transport equipment such as automobiles, shipsand aircrafts, as well as various electric appliances and electroniccomponents.

According to the embodiment described above, the following advantagesare achieved.

(1) The cleaning agent for alloy material contains an anionic surfactanthaving an SO₃M group and has a pH in a range between 1.5 and 4,inclusive. Therefore, foreign matters attached to the alloy materialsurface are easily removed and corrosion of the alloy material surfaceis suppressed. Accordingly, a cleaning agent for alloy material isprovided that is capable of increasing the cleanliness of the alloymaterial surface and suppressing deterioration in quality due tocorrosion of the alloy material surface.

(2) The cleaning agent for alloy material preferably contains an organicacid. In this case, the pH of the cleaning agent for alloy material iseasily adjusted within the above pH range and the effects based on thepH are more increased.

(3) It is preferable to use an anionic surfactant of sulfonic acid typein which the counter ion represented by “M” in the SO₃M group is ahydrogen ion among the anionic surfactants. In this case, the pH of thecleaning agent for alloy material can be easily adjusted to 4 or less.

(4) The method for producing an alloy material contains the cleaningstep of cleaning the alloy material using the cleaning agent for alloymaterial. According to the production method, an alloy material can beeasily obtained in which the cleanliness of the surface is improved anddefects due to surface corrosion are reduced.

(5) The temperature of the cleaning agent for alloy material in thecleaning step is preferably 60° C. or below. In this case, corrosion ofthe alloy material surface is further easily suppressed.

(6) The cleaning step is preferably performed after the polishing stepin which the alloy material is polished using a polishing composition.In this case, the polishing composition having attached to the alloymaterial in the polishing step can be easily removed. When, for example,an aluminum alloy is polished using a polishing composition containingabrasive grains such as colloidal silica, and then the alloy is cleanedusing the cleaning agent for alloy material according to the presentembodiment, foreign matters such as abrasive grains can be easilycleaned away.

(7) In the cleaning step, the alloy material and the cleaning agent foralloy material are preferably brought into contact with each otherbefore the polishing composition having attached to the alloy materialin the polishing step is dried. In this case, the alloy material surfaceis prevented from being dried during the period from the end of thepolishing step to the beginning of the cleaning step. Thus, the stickingof the ingredients in the polishing composition to the alloy materialsurface is suppressed. Therefore, cleanliness of the alloy materialsurface can be more improved. Since the alloy material surface incontact with the cleaning agent for alloy material is protected by thecleaning agent for alloy material, corrosion of the alloy materialsurface is suppressed. Particularly, it is preferable to bring the alloymaterial and the cleaning agent for alloy material into contact witheach other by immersing the alloy material into the cleaning agent foralloy material.

(8) A mirror surface formed by polishing is advantageous in that themirror surface is better in durability than that formed by, for example,plating or coating. Particularly, the mirror surface formed by polishingusing a polishing composition has higher flatness, thereby beingadvantageous in that the alloy material having the more highly accuratemirror surface can be obtained. In such an alloy material having thehighly accurate mirror surface, deterioration of cleanliness andcorrosion of the mirror surface are visually recognized easily.Therefore, higher cleaning performance and lower corrosiveness arerequired for the cleaning agent for alloy material applied to such analloy material having a highly accurate mirror surface. The cleaningagent for alloy material according to the present embodiment isparticularly advantageous in that the cleaning agent for alloy materialcan improve the cleanliness of the mirror surface having been polishedusing the polishing composition, while maintaining high flatness of themirror surface.

The embodiment described above may be modified as follows.

-   -   The first cleaning stage may be performed in a manner in which        the cleaning agent for alloy material is circulated in the state        where the alloy material is immersed in the cleaning agent for        alloy material in the cleaning vessel. In the first cleaning        stage, the circulation of the cleaning agent for alloy material        may be used in combination with the ultrasonic wave exposure        described above.    -   The ultrasonic wave exposure in the first cleaning stage may be        omitted.    -   In the first cleaning stage, the alloy material and the cleaning        agent for alloy material may be brought into contact with each        other by spraying the cleaning agent for alloy material to the        alloy material surface or pouring the cleaning agent for alloy        material over the alloy material surface.    -   As the preliminary stage for the first cleaning stage, the alloy        material may be pre-cleaned with a cleaning agent other than the        cleaning agent for alloy material described above.    -   The first cleaning stage may be performed after the polishing        composition having attached to the alloy material in the        polishing step is dried.    -   The second cleaning stage may be performed in a manner in which        water is circulated in the state where the alloy material is        immersed in the water in the cleaning vessel. In the second        cleaning stage, the circulation of the water may be used in        combination with the ultrasonic wave exposure described above.    -   The second cleaning stage may be performed by means of spraying        water to the alloy material surface or pouring water over the        alloy material surface.    -   In the cleaning step, scrub cleaning using, for example, a PVA        sponge, a nonwoven fabric or a nylon brush may be carried out.        The cleaning step may be performed using a polishing apparatus.        That is, in the cleaning step, the alloy material may be        scrub-cleaned with a polishing pad, while pouring the cleaning        agent for alloy material or water over the alloy material.    -   The water used in the second cleaning stage may be changed to an        organic solvent such as an alcohol, a mixed solvent of water and        an alcohol or the like, a liquid containing an ingredient such        as a rust inhibitor, or the like.    -   The first cleaning stage or the second cleaning stage may be        repeated a number of times.    -   In the cleaning step, the surface to be cleaned may be the        entire surface of the alloy material or a part of the alloy        material surface.    -   The shape of the alloy material is not particularly limited. The        alloy material may have a surface of any shape including, for        example, a flat surface, a curved surface such as a convex or        concave surface, and a spherical surface.    -   The alloy material may have the mirror surface over its entire        surface or over a part of the surface.    -   The alloy material may be, for example, a plate-like body having        the mirror surfaces on both sides or that having the mirror        surface on a single side only.    -   The cleaning agent for alloy material may be applied to an alloy        material having no mirror surface. That is, the alloy material        to be cleaned may be also an alloy material that has been        subjected to the polishing step and has a surface other than the        mirror surface. Furthermore, the alloy material to be cleaned is        not limited to an alloy material that has been subjected to the        polishing step, but the alloy material to be cleaned may be also        a cut alloy material, for example. Even in this case, when the        cleaning agent for alloy material is used, foreign matters        attached to the alloy material surface are easily removed and        the deterioration in quality due to the corrosion of the alloy        material surface can be suppressed.    -   Plating or coating may be applied to the alloy material after        being cleaned with the cleaning agent for alloy material. In the        case of the alloy material having a mirror surface, however, the        mirror surface is preferably left exposed in view of an        appearance or durability.    -   The cleaning agent for alloy material may be prepared by        diluting an undiluted solution of the cleaning agent for alloy        material with, for example, water.    -   The cleaning agent for alloy material that has been once used        for cleaning the alloy material can be recovered and reused for        cleaning again. For example, solid matter contained in the used        cleaning agent for alloy material recovered from the cleaning        vessel may be removed by filtration or the like, and then the        cleaning agent can be reused. An unused cleaning agent for alloy        material may be supplied to the cleaning vessel together with        the used cleaning agent for alloy material as necessary. Reuse        of the cleaning agent for alloy material is advantageous in that        the environmental load can be reduced through decreasing the        amount of the cleaning agent for alloy material to become waste        fluid and in that the costs required for cleaning can be reduced        through decreasing the amount of the cleaning agent for alloy        material used.

The technical ideas obtainable from the above embodiment will hereafterbe described.

(a) A cleaning agent for alloy material containing, as the anionicsurfactant described above, an anionic surfactant of sulfonic acid typein which the counter ion represented by “M” in the SO₃M group is ahydrogen ion.

(b) A cleaning agent for alloy material containing an anionic surfactanthaving an SO₃M group (where M represents a counter ion) and having a pHin a range between 1.5 and 4, inclusive, the cleaning agent for alloymaterial being applied to the alloy material having been polished usinga polishing composition, the polishing composition containing colloidalsilica and an oxidizing agent and having a pH in a range between 8 and12, inclusive.

(c) A cleaning agent for alloy material applied to the alloy materialhaving a mirror surface having been polished using a polishingcomposition, the cleaning agent for alloy material being used in theapplication for cleaning the mirror surface thereof.

EXAMPLES

Then, Examples and Comparative Examples will be described.

The cleaning agents for alloy material having compositions 1 to 10 shownin Table 1 were prepared, respectively. For the cleaning agents foralloy material having the compositions 1 to 3, 5 to 7, and 9, theanionic surfactant was first diluted with water, and then a pH adjusterwas added thereto. The pH of each cleaning agent for alloy material isas shown in the column “pH” in Table 1. The pH was measured for eachcleaning agent for alloy material at 20° C.

An alloy material was produced using each cleaning agent for alloymaterial having each of the compositions 1 to 10. As shown in Table 2,the cleaning agents for alloy material having the compositions 1 to 7were used in Examples 1 to 7, respectively, and the cleaning agents foralloy material having the compositions 8 to 10 were used in ComparativeExamples 1 to 3, respectively.

In Example 1, a plate-like aluminum alloy of 32 mm×32 mm×5 mm in sizewas used as an alloy material. This aluminum alloy contains about 1% ofSi, Fe, Mn and the like in total.

First, a polishing step of polishing the alloy material was performedusing a polishing composition containing colloidal silica as abrasivegrains and having a pH of 10. In this polishing step, the alloy materialwas polished using a polishing pad of suede type not containing abrasivegrains until one surface of the alloy material became a mirror surface,while applying a constant pressure.

Then, the first cleaning stage was performed as follows. The alloymaterial after the polishing step was immersed in the cleaning agent foralloy material having the composition 1 in a first cleaning vessel. Thefirst cleaning vessel was transported to a second cleaning vesselequipped with an ultrasonic generator. The alloy material wastransferred into the second cleaning vessel and was immersed in thecleaning agent for alloy material having the composition 1 in the secondcleaning vessel. Then, the temperature of the cleaning agent for alloymaterial in the second cleaning vessel was elevated up to thetemperature shown in the column “Cleaning temperature” in Table 2 andthe cleaning agent for alloy material was exposed to an ultrasonic wavehaving a frequency of 750 kHz for 3 minutes, while maintaining theabove-described temperature of the cleaning agent for alloy material.The temperature of the cleaning agent for alloy material did not exceedthe temperature shown in the column “Cleaning temperature” in Table 2throughout the first cleaning stage.

Then, the second cleaning stage was performed as follows. The alloymaterial was transferred into a third cleaning vessel and immersed inpure water in the third cleaning vessel. Subsequently, the pure water inthe third cleaning vessel was exposed to an ultrasonic wave having afrequency of 430 kHz for 3 minutes.

Finally, the alloy material was taken out of the third cleaning vesseland was dried by blowing dry air.

In Examples 2 to 7 and Comparative Examples 1 to 3, the alloy materialwas polished, cleaned, and dried in the same manner as in Example 1except that the cleaning agent for alloy material was changed as shownin Table 2.

<Evaluation for Cleanliness>

While directing a spotlight on the surface of the alloy materialobtained in each Example or Comparative Example in a dark room, thelevel of the residual polishing composition on the alloy materialsurface was checked by visual observation. In the column “Cleanliness”in Table 2, “A” indicates a state where the residual polishingcomposition was not visually recognized over the entire mirror surfaceof the alloy material, “B” indicates a state where the residualpolishing composition in a slight level was visually recognized on themirror surface of the alloy material, and “C” indicates a state wherethe residual polishing composition was visually recognized over theentire mirror surface of the alloy material.

<Evaluation for Corrosion Suppression>

The corrosion level on the mirror surface of the alloy material obtainedin each Example or Comparative Example was checked by visual observationusing a differential interference microscope. In the column “Corrosionsuppression” in Table 2, “A” indicates a state where the corrosion wasnot visually recognized over the entire mirror surface of the alloymaterial, “B” indicates a state where the corrosion in a slight levelwas visually recognized on the mirror surface of the alloy material, and“C” indicates a state where the corrosion was visually recognized over ½or more of the mirror surface of the alloy material.

TABLE 1 Anionic surfactant pH adjuster Content Content [ppm by [% byKind mass] Kind mass] pH Composition 1 Dodecyl benzene 300 Citric 0.12.65 sulfonic acid acid Composition 2 Dodecyl benzene 500 Citric 0.12.68 sulfonic acid acid Composition 3 Dodecyl benzene 1000 Citric 0.12.61 sulfonic acid acid Composition 4 Dodecyl benzene 500 — — 2.90sulfonic acid Composition 5 Dodecyl benzene 300 Citric 0.2 2.15 sulfonicacid acid Composition 6 Dodecyl benzene 500 Citric 0.2 2.15 sulfonicacid acid Composition 7 Dodecyl benzene 1000 Citric 0.2 2.10 sulfonicacid acid Composition 8 — — Citric 0.2 2.16 acid Composition 9 Dodecylbenzene 500 Citric 2.5 1.30 sulfonic acid acid Composition 10 Sodiumdodecyl 200 — — 7.10 benzene sulfonate

TABLE 2 Evaluation Cleaning agent Cleaning Clean- Corrosion for alloytemperature liness suppression Example 1 Composition 1 40° C. A AExample 2 Composition 2 40° C. A A Example 3 Composition 3 40° C. B AExample 4 Composition 4 40° C. A A Example 5 Composition 5 40° C. A BExample 6 Composition 6 40° C. A B Example 7 Composition 7 40° C. B BComparative Composition 8 40° C. C B Example 1 Comparative Composition 940° C. A C Example 2 Comparative Composition 10 40° C. C A Example 3

As shown in Table 2, all of the evaluation results of Examples 1 to 7were “A” or “B”. On the other hand, in the Comparative Examples 1 to 3,the evaluation results for either of the cleanliness or the corrosionsuppression were “C”, which were inferior evaluation results to those ofExamples 1 to 7.

Influence of Cleaning Temperature

The alloy material was produced using the cleaning agent for alloymaterial having the composition 2 at varied cleaning temperatures andevaluated for the cleanliness and the corrosion suppression. At cleaningtemperatures from room temperature to 60° C., all the evaluations forthe cleanliness and the corrosion suppression were the same as those ofExample 2. On the other hand, at cleaning temperatures above 60° C., theevaluation results for the corrosion suppression tended to be inferiorto that of Example 2. Accordingly, the cleaning temperature in thecleaning step is advantageously set at 60° C. or below.

1. A cleaning agent for alloy material, comprising an anionic surfactanthaving an SO₃M group (where M represents a counter ion), wherein thecleaning agent for alloy material has a pH in a range between 1.5 and 4,inclusive.
 2. The cleaning agent for alloy material according to claim1, further comprising an organic acid.
 3. A method for producing analloy material, comprising a cleaning step for cleaning an alloymaterial using the cleaning agent for alloy material according toclaim
 1. 4. The method for producing an alloy material according toclaim 3, wherein the cleaning agent for alloy material has a temperatureof 60° C. or below in the cleaning step.
 5. The method for producing analloy material according to claim 3, further comprising a polishing stepperformed prior to the cleaning step, wherein the alloy material ispolished using a polishing composition in the polishing step.
 6. Themethod for producing an alloy material according to claim 5, wherein inthe cleaning step, the alloy material and the cleaning agent for alloymaterial are brought into contact with each other before the polishingcomposition attached to the alloy material in the polishing step isdried.